1. Field of Invention
The present invention relates to an airbag cushion for vehicles which can mitigate the risk of deployment of the airbag injuring an occupant.
2. Description of Related Art
Generally, an airbag system is installed in a vehicle to protect an occupant in the vehicle from impact during a vehicle collision.
In the airbag system, an airbag cushion is disposed in an airbag housing in a folded state under normal conditions. In a vehicle collision, an inflator rapidly supplies gas into the airbag cushion in response to the sensing of a sensor so that the airbag cushion deploys instantaneously, thus protecting the occupant from impact during the collision.
However, if the pressure in the airbag cushion when deploying is comparatively high to reliably reduce the risk of injury of the neck of the occupant, the back of the head of the occupant may strike the headrest of a seat due to instantaneous inflation pressure of the airbag cushion, resulting in the occupant injuring his/her head.
In an effort to overcome the above problem, as shown in FIG. 1, a technique was proposed, in which vent holes 2 are formed on opposite sides of the airbag cushion 1 so that when the airbag cushion 1 deploys, gas injected into the airbag cushion 1 is discharged early out of the vent holes 2 to prevent the airbag cushion 1 from striking the occupant because its pressure of inflation is excessively high.
However, in this conventional airbag cushion, because the vent holes open even at the initial stage of deployment of the airbag cushion, an excessive pressure loss may be caused during the deployment of the airbag cushion. Thereby, the airbag cushion may not be able to correctly restrain the occupant at the initial stage of the vehicle collision, thus inducing a change in the injury conditions of the occupant.
To solve this problem, an active vent was proposed. The active vent is provided in an airbag module so that an airbag cushion is rapidly deployed by high pressure at the initial stage of its deployment, and the pressure in the airbag cushion is released at a point of time at which the weight of the occupant is applied to the airbag cushion.
However, additional installation expenses are required for the active vent, thus increasing the production cost of the airbag module.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.